constant λ iRR was successfully applied to FTIR, UV–vis, DSC and GC data.
iRR significantly outperforms ridge regression and partial-least square regression.
iRR is faster than iPLS and prevents possible under- and overfitting of iPLS.
FTIR, UV–vis and DSC can determine adulteration of hempseed oil (RMSEP<2%).
FTIR-iRR can attain very high accuracy and very low limit of detection.